The EPA said it would allow the sale of 10% ethanol, or E10, gasoline with a higher Reid Vapor Pressure (RVP) beginning September 1, about two weeks earlier than normal.
U.S. gasoline prices have risen due to the Iran war. On Thursday, pump prices for regular gasoline averaged $4.10 per gallon, up from about $3.13 a gallon a year ago, according to AAA motor club data.
High pump prices are a vulnerability for Trump and his fellow Republicans as they try to retain control of Congress in the November midterm elections.
U.S. Energy Secretary Chris Wright, who met this week with oil refiners in Midland, Texas, said that the administration would take steps over the coming days to control fuel prices.
The EPA said it also waived state-level controls on gasoline in Texas, Arizona and California that extend beyond September 15, for the maximum period allowed of 20 days.
"As the EPA has done all summer, we will be monitoring gasoline supplies in those states and will be prepared to extend the waiver through a subsequent action as long as necessary to ensure adequate supplies of gasoline to consumers," the agency said.
Analysts were divided on how much the move would lower prices for consumers.
"Hastening winter-grade gasoline into supply via an RVP waiver is legally defensible, can be done with the stroke of a pen, would engender minimal political blowback, and, most importantly, would genuinely help to alleviate a supply crunch and offer immediate pump price relief," Rapid Energy said in a note to clients on Thursday.
Tom Kloza, chief energy adviser at Gulf Oil, said the impact would be limited unless New York and New Jersey also agree to go along with waiving state-level controls.
